is it ok to trace around the inner black gasket ring that comes with the subwoofer to get the size for the cut out hole?

measure it and see.

However it's still not going to be completely accurate because they are flexible and probably move while drawing. They can slightly stretch as well so you wouldnt really know if it's a perfect circle either.

no, the mounting gasket won't give you a perfect circle if you trace it.

i usualy take a nail and tap it into the center of the circle. take a peice of string and tie a pencil to it. then measure HALF the lenght of the mounting diameter and tie to nail. I.E. if the mounting diameter was 12", tie the string onto the pencil, then measure 6", then tie at the nail. that way when you make a circle. you are making a 12" perfect circle.

Edited March 8, 200817 yr by fbi90909

i do the same thing as the that guy^ but i use a dowel rod so i can slide it back and forth for whatever size hole i need

i posted this somewhere else on this forum too -

When you get your radius, take something sharp, like a nail and a piece of short, narrow flat wood and run it into one part of the wood. Measure out the radius on this piece of wood. Drill a hole that a pencil can fit through tightly as point B. Then run the pencil through and there is no way it will get away from ya. You have to make a perfect circle with that.